1. Field of the Invention
This invention relates to a method of making an abrasive tape used for polishing a magnetic head. This invention particularly relates to preparation of an abrasive composition which is to be applied onto a flexible substrate of the abrasive tape.
2. Description of the Prior Art
There has heretofore been known a method of making an abrasive tape by preparing an abrasive composition from abrasive grains and a binder, applying the abrasive composition onto a flexible substrate of continuous length, and then drying the applied abrasive composition.
In the conventional method of making an abrasive tape, it is necessary to decrease separation of the abrasive grains from the abrasive tape and to improve the smoothness of the abrasive coating film.
In order to solve these problems, it is necessary to prepare an appropriate abrasive composition. For this purpose, preparation of the abrasive composition should be carried out by appropriate processing. Specifically, in order to prevent separation of the abrasive grains from the abrasive tape, it is necessary to increase the bond strength between the abrasive grains and the binder. Also, in order to improve the smoothness of the abrasive coating film, it is necessary to uniformly disperse the abrasive grains in the form of primary grains in the binder. Processing capable of solving the aforesaid problems should be carried out with consideration to these requirements.
However, with the conventional method of preparing an abrasive composition by use of a ball mill as disclosed in, for example, Japanese Unexamined Patent Publication No. 55(1980)-129927, it is not always possible to substantially improve the bond strength between the abrasive grains and the binder within a short period, and to disperse the abrasive grains sufficiently up to the form of primary grains. Also with the method of preparing an abrasive composition by use of a roll mill as disclosed in, for example, Japanese Patent Publication No. 53(1978)-44714, it is not always possible to substantially improve the bond strength between the abrasive grains and the binder, and to disperse the abrasive grains sufficiently up to the form of primary grains.